Molecular characterisation of Aspergillus flavus on imported maize through gazetted and ungazetted points of Entries in Kenya

Paper Details

Research Paper 06/01/2024
Views (1518) Download (28)
current_issue_feature_image
publication_file

Molecular characterisation of Aspergillus flavus on imported maize through gazetted and ungazetted points of Entries in Kenya

Joseph Oduor Odongo, Paul O. Angi’enda, Bramwel Wanjala, Catherine Taracha, David M. Onyango
Int. J. Micro. Myco.18( 1), 1-22, January 2024.
Certificate: IJMM 2024 [Generate Certificate]

Abstract

Maize is a vital staple crop in Kenya, serving as a primary source of food and feed. Contamination of maize (Zea mays) by Aspergillus flavus  and the subsequent production of aflatoxins pose significant threats to food safety and human health. The risk of A. flavus contamination on imported maize at both gazetted and un-gazetted points of entry has not been extensively studied. The primary objective of this study was to examine the genotypic, phenotypic, and aflatoxigenic traits of A. flavus biovars derived from imported maize at Gazetted and Un-gazetted Points of Entries in Kenya. Furthermore, the study sought to establish the phylogenetic relationships among the identified A. flavus strains. A total of 600 imported maize samples were tested for aflatoxin contamination using the Total aflatoxin ELISA test. Out of 600 samples, 4.17% tested positive and were further subjected to morphological and molecular studies.  The morphological analysis revealed the presence of 13 biovars of A. flavus. Micro-morphologically, variations were observed in spore color, size, structure, conidiophore structure, and vesicle shape. The specific primers Calmodulin (CaM), the ITS1-5.8S-ITS2 region of the ribosomal DNA was successfully amplified in 10 out of the 13 biovars that were presumed to be A. flavus, confirming their positive identification as A. flavus. A single band of approximately 700 bp, which corresponds to the expected size of the ITS region in Aspergillus flavus, was observed in 10 out of the 13 biovars. This indicates the presence of A. flavus DNA in those biovars. The amplification of the ITS region provides a specific molecular marker for the identification of A. flavus. These findings highlight the significance of aflQ (ordA) and aflD (nor-1) genes as reliable markers for evaluating the aflatoxigenic potential of A. flavus biovars. Regarding aflatoxigenicity, DV-AM   method was used, and qualitative analysis was conducted. Out of the 13 biovars of A. flavus biovars tested, 23.08% exhibited aflatoxigenicity, while the remaining 10 biovars did not show any aflatoxigenicity. These findings indicate the presence of both aflatoxigenic and non-aflatoxigenic strains of A. flavus among the imported maize samples. The phylogenetic analysis revealed that Taxon 31 (AY495945.1 Aspergillus flavus biovar 92016f aflR-aflJ intergenic region partial sequence) and Taxon 32 (NR 111041.1 Aspergillus flavus ATCC 16883 ITS region from TYPE material). This genotypic and phenotypic characterization provides valuable information for understanding the diversity and potential toxigenicity of A. flavus strains on imported maize. This study contributes to the understanding of the genotypic and phenotypic characteristics of A. flavus on imported maize in Kenya.

VIEWS 159

Abbas HK, Accinelli C, Zablotowicz RM, Abel CA, Bruns HA. 2013. Prevalence of aflatoxin and fumonisin in corn (maize) and peanut cake from hens laying contaminated eggs destined for human consumption in Pakistan. Food Additives & Contaminants: Part A, 30(1), 169-180. DOI:10.1080/19440049.2012.748706

Abdallah MF, Girgis GN, Khedr AHA, Ali EF, Abdul-Raouf UM. 2018. Genotypic diversity and antifungal susceptibility of Aspergillus flavus isolated from maize grains in Egypt. Journal of Genetic Engineering and Biotechnology, 16.

Amaike S, Keller NP. 2011. Aspergillus flavus. Annual Review of Phytopathology 49, 107-133.

Atehnkeng J, Donner M, Ojiambo PS, Ikotun T, Sikora RA, Cotty PJ, Bandyopadhyay R. 2014. Biological control agents for managing aflatoxin contamination in groundnut: A review. Agriculture 4(3), 197-217. DOI: 10.3390/agriculture4030197

Atehnkeng J, Ojiambo PS, Ikotun T, Sikora RA, Cotty PJ, Bandyopadhyay R. 2014. Evaluation of atoxigenic isolates of Aspergillus flavus as potential biocontrol agents for aflatoxin in maize. Food Additives & Contaminants: Part A, 31(2), 378-387.

Bensch K, Groenewald JZ, Dijksterhuis J, Starink-Willemse M, Andersen B, Summerell BA, Shin HD, Dugan FM. 2018. Species and ecological diversity within the Cladosporium cladosporioides complex (Davidiellaceae, Capnodiales). Studies in Mycology 89, 177-301.

Brown DW. 2005. Phylogenetic Analysis of Zipper-Positive Abdominal Aflatoxin-Producing Aspergillus Species. Mycologia 97(2), 498-504.

Brown DW. 2010. Phylogenetic Analysis and Mycotoxin Production Capability of Aspergillus Section Flavi from Brazil Nuts. Mycologia 102(4), 866-872.

Chen ZY, Brown RL, Rajasekaran K, Damann KE, Cleveland TE. 2008. Evaluation of thermotolerant strains of Aspergillus flavus for aflatoxin contamination and genetic variation. Journal of Food Protection 71(9), 1909-1914.

Diba K, Kordbacheh P, Mirhendi SH, Rezaie S, Mahmoudi M. 2007. Identification of Aspergillus species using morphological characteristics. Pakistan Journal of Medical Sciences 23(6), 867.

Diniz LE, Sakiyama NS, Lashermes P, Caixeta ET, Oliveira ACB, Zambolim EM, Zambolim L. 2005. Analysis      of AFLP markers associated to the Mex-1 resistance locus in Icatu progenies. Crop Breeding And Applied Technology, 5(4), 387.

Johnson LJ. 2015. Genetic Diversity and Population Structure of Aspergillus flavus Isolates from Maize Fields in Three Geographic Regions of the United States. Journal of Agricultural and Food Chemistry 63(41), 9016-9023.

Jones JP. 2012. Molecular identification of aflatoxigenic and non-aflatoxigenic Aspergillus species from maize (Zea mays L.). Mycotoxin Research 28(2), 89-96.

Kilonzo RM, Imungi JK, Muiru WM, Lamuka PO, Kuria EN. 2017. Genetic diversity and aflatoxin contamination of maize from eastern Kenya regions. Journal of Applied Biosciences 114, 11342-11351.

Kilonzo-Nthenge A, Monda E, Okoth S, Makori D. 2019. Aflatoxins and their fate in maize and maize-based products in Kenya: A review. Food Control 96, 219-225.

Kilonzo-Nthenge A, Monda E, Okoth S, Makori D. 2019. Aflatoxins and their fate in maize and maize-based products in Kenya: A review. Food Control 96, 219-225.

Lee T. 2019. Genetic Diversity and Population Structure of Aspergillus flavus Isolates from Maize in Thailand. Frontiers in Microbiology 10, 1997.

Liang Y, Yu J, Zhou T. 2015. Improving Aflatoxin B1 Production on Rice by Aspergillus flavus and Aspergillus parasiticus through Recombination of Cytochrome P450 Enzymes. Scientific Reports 5, 1–10. https://doi.org/10.1038/srep08260

Miller JD. 2016. Structure and Population Diversity of Aspergillus flavus from Maize in Thailand. Toxins 8(12), 368.

Odhiambo BO, Kilonzo RM, Njage PM, Okoth S. 2020. Aflatoxin contamination in maize: Current challenges and potential opportunities for mitigation in Sub-Saharan Africa. Toxins 12(10), 630.

Ojiambo PS, Ikotun T, Leke W, Sikora R, Mukalazi J. 2016. Variation in the pathogenic and genetic diversity among isolates of Aspergillus flavus link to aflatoxin contamination of peanut and maize in Kenya.

Probst C, Schulthess F, Cotty PJ. 2010. Impact of Aspergillus section Flavi community structure on the development of lethal levels of aflatoxins in Kenyan maize (Zea mays). Journal of Applied Microbiology 108(2), 600-610. DOI: 10.1111/j.1365-2672.2009.04432.x

Raju MVLN, Seetharami Reddi TV, Krishna TG. 2014. Development of a PCR-based method for detection and differentiation of Aspergillus flavus and Aspergillus parasiticus. Indian Journal of Microbiology 54(2), 202-206.

Samson RA, Houbraken J, Thrane U, Frisvad JC, Andersen B. 2019. Food and indoor fungi. Westerdijk Fungal Biodiversity Institute.

Samson RA, Houbraken J, Thrane U, Frisvad JC, Andersen B. 2014. Food and Indoor Fungi. CBS-KNAW Fungal Biodiversity Centre.

Sobolev VS, Neff SA, Gloer JB, Abbas HK. 2009. Characterization of novel volatile antimicrobials from the molds Aspergillus flavus, Aspergillus parasticus, and Aspergillus ochraceus. Toxins 1(1), 3-12. DOI: 10.3390/toxins1010003

White TJ. 1990. Amplification and Direct Sequencing of Fungal Ribosomal RNA Genes for Phylogenetics. In PCR Protocols: A Guide to Methods and Applications (pp. 315-322). Academic Press.

Xu J, Chen AJ, Zhang Y. 2016. Molecular approaches for rapid identification and diversity assessment of foodborne spoilage yeasts: A review. Journal of Food Science 81(1), M15-M22.

Yu J. 2016. Regulation of Aflatoxin Biosynthesis: Perspectives from Genomics Research. Methods in Molecular Biology 1398, 267-285.

Yu J, Chang PK, Cary JW, Wright M, Bhatnagar D, Cleveland TE, Payne GA. 2012. Comparative mapping of aflatoxin pathway gene clusters in Aspergillus parasiticus and Aspergillus flavus. Applied and Environmental Microbiology, 78(23), 7856-7866. DOI: 10.1128/AEM.01959-12

Yu J, Chang PK, Ehrlich KC, Cary JW, Bhatnagar D, Cleveland TE, Payne GA. 2004. Clustered pathway genes in aflatoxin biosynthesis. Applied and Environmental Microbiology 70(3), 1253-1262.

Yu J, Chang P-K, Ehrlich KC, Cary JW, Montalbano B, Dyer JM, Bhatnagar D, Cleveland TE, Payne GA. 2011. Clustered pathway genes in aflatoxin biosynthesis. Applied and Environmental Microbiology 77(24), 8479-8484. https://doi.org/10.1128/AEM.06367-11

Yu J, Payne GA, Nierman WC, Machida M, Bennett JW, Campbell BC. 2013. Aspergillus flavus genomics: Gateway to human and animal health, food safety, and crop resistance to diseases. In Advances in Applied Microbiology  84, 1-91.